To select the audio output device on a computer running the Windows Vista® operating system, follow these steps:
Click the "Start" button on the lower-left corner of the screen
Click "Control Panel"
In the Control Panel, click "Hardware and Sound"
In the Hardware and Sound menu, click "Manage audio devices"
In the "PLAYBACK" tab, highlight the Bluetooth® device
Once the Bluetooth device is selected, click "SET DEFAULT"
If you made any changes, click "Apply" and then click "OK" to close the window